Ask the Master Gardener: Clematis plants hardy enough to grow in Brainerd

Clematis is Minnesota’s showiest vine with flowers that range in size from 1-5 inches and comes in colors from pale whites and yellows to vivid red and deep purples.

Flowers growing on a trellis.
Two variations of Clematis plants that can grow in Minnesota — Jackmanni Superba (dark purple) and Blue Angel (lavender).
Contributed / Jennifer Knutson

Dear Master Gardener: I’m confused. I would like to plant Clematis flowers and I see them growing in Brainerd gardens. But everything I read about them says they are not hardy in our zone 3 area. How can this be?

A Clematis flower.
Another variation of Clematis plant, the Vancouver Starry Night.
Contributed / Jennifer Knutson
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Answer: Perhaps a little information about Clematis can help you. There are three kinds of Clematis and they differ from one another in how and when they flower and how they are pruned. Type 1 blooms in the spring on old growth, with buds forming the year before they bloom. Therefore, they should be pruned immediately after flowering and before buds form in July. Type 1 Clematis are typically not hardy to zone 3 and not recommended for our climate. Type 2 produces flower buds on both old (last year’s) and new (this year’s) wood. It further subdivides into two-flush (May/June on old wood and September on new wood) and continuous (June through September) bloom periods. Examples of type 2 two-flush Clematis are Miss Bateman and Nelly Moser. These should be pruned between flushes and only lightly. Examples of continuous bloomers are Dr. Ruppel and The President. Type 3 Clematis blooms on new growth and flowers continuously, July through September. They are usually pruned to the ground each fall or early spring, leaving only the lowest buds to encourage new shoots in the spring. Examples of Type 3 are the very hardy and popular purple Jackmanii and Madame Julia Correvon. Type 3 Clematis will probably perform the best in zone 3.

Yes, many Clematis varieties are listed as zones 4-9 but many zone 4 cultivors grow well here, especially those that flower on new wood since buds that must overwinter can easily freeze. Trust your local nurseries to stock only hardy varieties. A Clematis vine requires a structure — a trellis, a fence, a post — to climb on, though occasionally people let one crawl along the ground as a ground cover. The old advice in growing Clematis is that they like warm heads and cool feet, meaning that they like their tops in the sun and their roots kept cool with moisture and mulch. An eastern exposure or a southern one with some midday shade works well.
Clematis is Minnesota’s showiest vine with flowers that range in size from 1-5 inches and comes in colors from pale whites and yellows to vivid red and deep purples. There is even a lovely white native Clematis, Clematis virginiana (commonly called Virgin’s Bower) for those who favor natives. It is aromatic, hardy in zone 3, blooms August through September, and produces attractive seedheads.

Dear Master Gardener: I was at a friend’s house and asked about a shrub he has that I’ve never seen before. He said it is a New Jersey tea shrub. What can you tell me about it?

Answer: The New Jersey tea (Ceanothus americanus) is a native shrub found in upland prairies and savannas. It is low growing and rounded in shape and typically doesn’t get taller than 2 feet in Minnesota. It is suitable for a traditional landscape, wildlife garden or on a steep slope. If planted 2 to 3 feet apart it forms an attractive low hedge. The plant has glossy leaves and in mid-summer is covered with showy clusters of white flowers. Not only are the flowers beautiful, but they attract a wide array of pollinators, including bees and butterflies. New Jersey tea thrives in rich, well-drained soil and the deep tap root makes it very drought tolerant once it is established. Plant it in full to part sun. It blooms on new growth, like an herbaceous perennial.


On a historical note, it was quite popular during the Revolutionary War period to use the leaves as a substitute for imported tea. In addition, the Minnesota Chippewa used the roots mixed with water to treat a cough.

Dear Master Gardener: When can I plant tuberous begonia and caladium tubers in the ground?

Answer: Tuberous begonias and caladiums are great plants for the shade garden and can be planted in the ground as soon as nighttime temperatures are above 50 degrees. They are very sensitive to cold temperatures. Plant tuberous begonia tubers, which are shaped like a little brown bowl, hollow side up. For the best results plant the tubers in pots first and let them sprout before putting them in the garden. Then plant them in the garden about five inches apart and cover them with one inch of soil. Plant the top of caladium bulbs 1-1/2 to 2 inches below the surface with the eyes pointing up.

Dear Master Gardener: My friend had lovely lavender flowers in her cutting garden last summer that looked similar to small roses. What could they be?

Answer: It sounds like Eustoma, commonly known as Lisianthus, which are delicate, elegant flowers that do look like small roses. They are grown as an annual in Minnesota. Lisianthus hybrids are long-stemmed flowers that come in lavender, dark purple, various shades of pink, and white. They should be planted in moist, well-drained soil that is rich in organic matter, in full sun, and in an area protected from wind. Wait to plant them until after the last frost date (after Memorial weekend). They are very long-lasting cut flowers that can last two to three weeks in a vase. They are one of the most elegant, but unfortunately one of the most difficult flowers to grow. Buy them as plants at a garden center because they are very difficult to grow from seed and require seven months to flower. They can also be hard to find. If you are growing Lisianthus as a cut flower, singles are better than doubles for cut flowers.

You may get your garden questions answered by calling the new Master Gardener Help Line at 218-824-1068 and leaving a message. A Master Gardener will return your call. Or, emailing me at and I will answer you in the column if space allows.

University of Minnesota Extension Master Gardeners are trained and certified volunteers for the University of Minnesota Extension. Information given in this column is based on university research.

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